His visit to Vojvodina and talks with local authorities came after a warning from the European Parliament that inter-ethnic incidents were again happening in the province.
"We do not want to minimise the number and gravity of the incidents. They should be seen as a warning, and I am here to appeal to the authorities that those responsible for the incidents must be punished most harshly," Ljajic said.
The minister, however, noted that the number of incidents, which were mainly directed at members of the Hungarian minority, had dropped considerably since last year.
The question of the position of the ethnic minorities in Vojvodina was raised again following a series of incidents over the last few months, which prompted the European Parliament last week to pass a resolution expressing its concern over frequent violations of human and minority rights and the absence of law.